Field of the Invention
The invention relates to a data card, a process for manufacturing the data card (chip card) and an apparatus for manufacturing the data card. The data card is formed of a top card layer and a bottom card layer sandwiching a module element there between. The module element has integrated circuit elements for processing and storing personal data.
Such a data card and a corresponding process for its manufacture are disclosed, for example, by British Patent Application No. 2 279 907 A. The application teaches a sheathing element holding integrated circuits embedded between two card top layers of PVC and between two intermediate layers of polyester, the latter being coated on both sides with a thermally activatable adhesive. The intermediate layers serve for laminar reinforcement and consequently as a guard against the sheathing element breaking out of the PVC layers.
On account of their high functional flexibility, the application possibilities for data cards, generally configured in a check card format, have become extremely varied and, with the increasing computing power and storage capacity of the integrated circuits, are continuing to increase. In addition to the traditional fields of application for data cards in the form of health insurance cards, flex time registration cards, and phone cards, there will be future applications in the fields of electronic payment, computer access control, protected data memories and the like.
With regard to the method of coupling the data card to a terminal or a reader, a distinction is made between data cards with contacts and so-called contactless data cards. In the case of a data card with contacts, the electrical bonding takes place by a metallic contact area with contact elements which are usually standardized in accordance with an ISO standard. It is true that, on account of the increasing production experience of manufacturers, it has been possible for the reliability of the data cards with contacts to improve, so that for example the failure rate of phone cards over a service life of one year is less than one per thousand. However, as before, contacts are one of the most frequent sources of faults in electromechanical systems. Malfunctions may be caused, for example, by soiling or wearing of the contacts. If used in mobile equipment, vibrations may result in short-term contact interruptions. Since the contacts on the surface of the data card are connected directly to the inputs of the integrated circuit, there is, in addition, the risk of electrostatic discharges being able to weaken or even destroy the integrated circuit in the interior of the card.
These technical problems are obviated by the contactless data card. In addition to these technical advantages, the contactless data card also has a series of interesting new application possibilities for the card issuer and the card user. For example, contactless data cards do not necessarily have to be inserted into a card reader, but instead there are systems which operate over a range of up to one meter. A wide field of application is, for example, that of local public transport, where as many people as possible have to be registered in as short a time as possible. In addition to further advantages, the contactless data card has the benefit that no technical elements are visible on the card surface, so that the visual configuration of the card surface is not restricted by magnetic strips or contact areas. The disadvantages of the currently available contactless data cards are, in particular, associated with the additional components such as transmission coils or capacitor plates, which have to be integrated into the card. This has the result that, to date, the manufacture of contactless data ards is distinctly more expensive than the comparable cards with contacts. In addition, the electronics required in the contactless data card for the contactless transmission of electric signals to the terminal are more complex. Suitable in principle for this are circuits which permit signal transmission by microwaves, optical signals, capacitive or inductive coupling. The flat form of the data card is most compatible with capacitive and inductive coupling. At present, most contactless cards use inductive transmission devices, by which both data and energy transmission can be realized. Thus, one or more induction coils are integrated in the card body as coupling elements. The transmission of electric signals takes place on the principle of the loosely coupled transformer, the carrier frequency lying, for example, in the range between 100 and 300 kHz or at some MHz, in particular the radio frequency of 13.56 MHz. Required for this are induction coils having coil areas significantly greater than the base area of the semiconductor chip, of the order of magnitude of about 10 mm.sup.2, and typically about 30 to 40 cm.sup.2. The induction coils have to be electrically bonded in a suitable way to the circuit located on the semiconductor chip. In this case, the semiconductor chip is initially positioned, fixed and electrically bonded on an intermediate carrier.
Subsequently, for protection against environmental effects, an encapsulation is provided, preferably by a thermoset polymer composition. The carrier supporting the semiconductor chip, which is initially in the form of a separate component and is usually also referred to as a data (chip) module, is subsequently electrically bonded, preferably by welding, soft or hard soldering, to the induction coil. The induction coil generally has only few turns and is of a flat configuration, and the support is finally laminated into the card body to complete the data card.
The materials, the structural configuration and the manufacture of the card body of a data card are essentially determined by the functional elements of the card and also by the loading to which the card will be subjected to when in use. Currently customary materials for data cards are polyvinylchloride (PVC) which is the least expensive of all available materials and covers a wide range of use, acrylonitrile-butadiene-styrene (ABS) which is distinguished in particular by high strength and temperature resistance, and polycarbonate which permits a long service life but is more expensive. For manufacturing a data card, generally the laminating process is used, in which various films including outer films and inlet films of the data module, which are generally in the form of a separate, prefabricated component, are firmly welded to the card body. With this process, high demands for the quality of the bond between the data module and the card body can be met. It being virtually impossible for the chip to be detached from the card without destroying the latter. Usually, before being joined together, the outer films are provided with a recess which is produced by milling and into which the data module is adhesively fixed. To even out existing height differences of substructures of the data module and to fill cavities including recesses and holes which have been produced in advance by punching and/or milling and into which the data module can be inserted, use is made of intermediate layers of thermoplastic films. A disadvantage of laminating on such intermediate layers is that, on account of a multiplicity of available data (chip) modules with different dimensions and overall heights and with different configurations of the substructures, complete uniformity or evening out cannot be achieved in the mass production of data cards. In addition, the intermediate layers provided with recesses and openings for the purpose of height compensation require a certain manufacturing expenditure, which contributes to making the data cards produced in large numbers more expensive.